Differential mixer



June 14, 1960 w. D. 11EAGUE, JR 2,940,696

DIFFERENTIAL MIXER Filed April 27, 1955 WALTER D. TEGUE JR.

DIFFERENTIAL MIXER Walter Teague, Jr., Alpine, NJ., assignor to Bendix Aviation Corporation, Teterboro, NJ., a corporation of Delaware Filed Apr. 27, 1955, Ser. No. 504,284

6 Claims. (Cl. 244-83) This invention relates generally to a steering system for aircraft.

Aircraft; of the flying wing type have a pair of surfaces, known as elevons, which operate both as elevators and as ailerons. Operating the two surfaces in the same direction controls the pitch attitude of the craft so'that the surfaces act as the elevators of conventional aircraft. Operating the Vsurfaces in different directions, on the other hand, controls the roll attitude of the craft so that the surfaces operate as the ailerons of conventional aircraft. Sometimes, to control the aircraft, it is necessary to control the two surfaces so that both surfaces move in the same direction with respect to their normal position to change the pitch attitude and yet, at the same time, move differentially with respect to each other.

In accordance with the present invention, movement of the surfaces may be effected by the operation of a conv the controller vto movement of the surfaces may be individually adjusted for each mode of operation.

An object of the present invention, therefore, is to provide novel means for operating the elevons of a craft selectively in the same and/ or different directions.

Another object is to provide a novel means for operating the elevons of an aircraft differential with respect to a reference position and for displacing the reference from a normal datum position.

Still another object is to provide a novel means for changing the ratio of movement of a controller to the resultant movement of the control surface of the craft.

A further object is to provide a novel means for operating the elevons of an aircraft in response to actuation of a manual controller and having the relative movement ment for actuating the elevons of an aircraft in the same g t or different direction by the movement of a controller, a mixer being provided to respond to the movements of the controller to provide simultaneous unidirectional or dierential action ofgthe surfaces and a ratio changer for each manner of movement whereby the ratio of controller movement to surface movement may be varied for longitudinal movement at one ratio and fore and aft movement at another ratio.

The foregoing and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example. It is to ybe expressly understood, however, that the drawing is for the purpose of illustration andV description only, and is not intended as a definition of the limits of the invention.

The single sheet of drawing illustrates a control'system for the elevon surfaces of an aircraft in accordance with the present invention.

.Patented yJune 14, 1960 LCC Turning now to the drawing, the steering system for the left elevon 10 and the right elevon 12. comprises generally a mixer 14, an aileron ratio changer 15, an elevator ratio changer 16, and a manual controller 18. Movement of controller 18 in a lateral direction displaces the elevon surfaces in opposite directions, and movement in a fore and aft direction displaces the surfaces in the same direction.

Mixer 14 receives the aileron and elevator controller actions to .produce an output which is a Acomposite of the differential and unidirectional `output for the elevons.

The mixer comprises a pair of levers 20v and 21 which are pivoted by pins 22 and 23 to supporting arms 24and 25 and which have their ends connected together. by member 27 and pins 28 and 29. The other ends 30* and 31 of these levers are connected by suitable conventional means to the left and right elevon surfaces 10 and 12, respectively. p lTo obtain a differential action for the elevon surfaces, pin 29 is positioned by a member 32 which is actuated through a series of linkages extending from controller 18. Member 32 is pivotally connected to one arm 33 of a shaft 34 Whose other arm 35 is connected by a member 37 to the arm 38 of a second shaft 39 whose arm 40 is connected by a member 41 to arm 42 of another shaft 43 whose arms 44 and 45 constitute a portion of the ratio changer 15. The ratio changer, in turn, is connected to the manual controller 18 through a series of linkages.

Ratio changer 15 for the aileron channel and 16 for the elevator channel may be identical so only'ratio changer 15 will be described in detail; the corresponding parts of the other ratio changer 16, however, will be givenprime numbers. The purpose of these ratio changers isf to change the relative displacement of the control surface for a given displacement of the manual controller so that a given displacement of the controller will effect the same aerodynamic action on the craft despite changes in the parameters of flight and the ratio changers maybe of a type described and claimed in copending application Serial No. 504,270, filed April 27, 1955 by Walter D. Teague, J r., and assigned to Bendix Aviation Corporation.

Ratio changer V15 comprises a polygon whichis in the nature of a parallelogram having a pair of equal sides 44 and 46 and apair of equal sides 45 and 47. The input tothe ratio changer is supplied through arm 51 of a shaft 52'whose arm-53 is connected by member-.54 to arm 55 of another shaft 56 whose arm 57 is connected byv member 59 to the manual controller 18. Thus, the Vlateral displacement of controller 18 rotates shaft 52 about its axis; and since arm 51 is connected by member 66tothe pivot pin 67 joining arms 46 and 47, pin 67 is also rotated. The extent of displacement of pivot pin 67 in response to a given angular displacement of shaft 52 depends upon the position of pivot 67 relative to shaft 52. This position'is determined by the aileron ratio changer actuator 66 which positions a shaft 61 connected to arm 45 through arm 62. of a shaft 63 whose arm- 64 is connected by member 65 to arm 45. Thus, the rotation of shaft 63 by actuator 66 rotates arm 45 about shaft 43 on which the arm 45 is rotatably mounted and positions pin 67 relative to shaft 52, and the more nearly pin 67 approaches shaft 52, the smaller the extent of motion of pin 67 relative to the turning of shaft 52.. Conversely, the greater the distance of pin67 from shaft 52, the greater will be the motion of shaft 52. VThe actuator 61 for positioning pin 67 is operable in response to a ight parameter of the craft andis illustrated herein as being operable in responsetonchange in altitude of the craft as measured by a conventional a1- titudecontrol 60s.

Due to the parallelogram-like arrangement, the movement of 67 rotates shaft 43 whose arm 42 moves ypin 3 Y 29 "through linkage 41, 37, and 32. The movement of pin 29rot'ates levers 20 and 21 about pivots 22 Aand 23. This exerts a push, for example, on one elevon surface to. push it upwardly and a pull on the other to pull it downwardly. Thus, 'these actions, in response 'to the 'movements of controller 18 in a lateral direction, displace 'the elevon surfaces differentially to control the AYcraft aboutthe roll axis.

Y. While the craft is being controlled about the roll axis by the relative displacement of the surfaces, the craft may also be placed in a desired pitch attitude. To this end, the longitudinal movement of the controller 1S by Way of a'sutable mechanical connection 80 and arm 81 rotates a shaft 82 whose 'arm 83 through a member S5 supplies the input tofthe 'ratio changer 16 `which,'as discussed above, is identical to rthe ratio changer 15. Theoutput of Vther'atio changer 16 istransrnitted Vby way of member 95, arm 96, shaft 497, arm 98, and member'9`9 lto V10S'of 4sllraft 106.- VArm 107 is connected to a pair of members 109 `'and -1-10 which angularlyfdisplace arms 111.7ai1d 112 of shafts 113 and 114Whose arms 24 and 25 support pivot pins 22 .and 23. Thus, movement of arm 107 either pulls pins 22 and 23 together'or spreads them apart. If, for example, pins 22 and 23 be pulled together elevons 10 and 12 are displaced downwardly; and vif the pins be spread apart, the elevons are pushed upwardly. Thus, fore and aft movement of controllerf18 displaces surfaces and 12 in the same direction.

From the foregoing it `can be seen that the elevons 10 land 13 may be displaced in the same direction and also be displaced differentially at the same time. For example, the `elevons may be displaced upwardly by the displacement of stick 1S `in a fore and aft direction which spreads 'pins 22 and 23 apart. At the same time,the stick may lbe displaced in a lateral direction thereby moving pivot -pin 29 and rotating levers 20 and 21 about pins 22 and -23 'to differentially displace the elevons.

The foregoing has presented a novel steering system for craft of the type having tWo control surfaces which` are displaced together in the same direction to control the pitch attitude of the craft and displaced differentially to control the roll attitude. The surfaces may be displaced differentially and yet be displaced in relatively the' same direction from' the normal reference position.' The 6X,- tent ofdisplacement of the surface differentially in response to displacement of the controller may be adjustedV to provide one ratio of controller 'to surface movement, 'and-the extent of displacement of the surfaces in the same direction in response to displacement of the controller may be adjustedl independently to give a different ratio of controller to surface movement. i

' What is claimed:

v1. In a controlsystem for an aircraft having aY pair of `surfaces which are displaceable in the same direction to control the pitch attitude of the craft and in dierent directions'to control the roll attitude of the craft, acontroller capable of movement in a fore and aft and in a lateral direction, whereby movement o-f said controller in iand two sides pivoted to said arms and pivoted together -at a common pivot with a link connected to said common pivot for receiving said input movement land means 'forv Vangularly displacing said common pivot relative to said input, whereby. the vratio of input from said controller to adjusted input for said mixer is changed, and means re sponsive to said output for moving said surfaces.

2. A control system for an aircraft having a controller movable in a longitudinal and a lateral direction for operating control surfaces of a craft to maneuver the craft about its respective pitch and roll axes; comprising means operatively connecting "safi'd controller to said surfaces to effect movement of said surfaces in one sense upon longitudinal movement of said controller and movement of -s'a'id surfaces in another sense' upon lateral movement of said controller, .said connecting means including means for adjusting the ratio of movement of said controller to the resulting movement of said sur-faces in said one and said other "senses, motor means for actuating said ratio adjusting means, and altitude responsive means to control said motor -rncans in accordance with the prevailing altitude of the craft during flight.

3. A mixer for operating elevon surfaces of an aircraft 'in response 'to a main controller member vrnov'able in one sense for ordering elevon surface movements for controlling the pitch of the aircraft and movable in `another 'sense for ordering elevon surface movements for controlling -the 'roll attitudes of the aircraft; said 'mixer 'comprising a pair 'of levers, means 'for pivotally supporting each lever intermediate its ends, a member connecting one elevon to one end of one of said levers, a member connectingfthe other elevon 'to the end of the other of said levers, means for connecting the other ends of said levers together, means operatively connecting said controller member to said lever connecting means for moving 'said leverconnectingv means relative to said levers in response to roll attitude controlling movements of said controller member, whereby said levers are displaced in the Same direction about said pivot means to exert a different action on each of said elevons, other means operatively connecting said controller member to said pivotal supporting means, and said other connecting means operable in one sense for drawing together and in another Ysense for `spreading apart said pivotal supporting means in response to pitch attitude controlling movements of said controller member, whereby said levers exert a unidirectional action on said elevons.

4. control system for an aircraft having a controller movable in a longitudinal and a lateral direction for op` -erating control surfaces of a craft to-maneuver the craft about its respective'pitch and roll axes, comprising supporting linkage means movably mounted on said craft,

other linkage means pivotally movable on and supported =by saidr supporting linkage means, said other linkage means operatively connected to said surfaces, whereby said surfaces are moved in one sense when said other linkage means is moved relative to said supporting link- "for operatively .connect-ing said controller to said other vlinkage means, and said controller being movable in one senseV to effect-through said first connecting means movement of said control surfaces in said other sense and said controller movable in another sense to effect through saidsecond connecting means movement of said control surfaces in said one sense to control said craft about its respective pitch and roll axes.

5. The combination defined by claim 4 in which said first and second connecting means include means for individually' adjusting the ratio of the movement of said controller to the resulting movement of said surfaces in said one and said other senses.

6. The combination defined by claim 4 in which said lfirst and second connecting means include means for individually Vadjusting the ratio of the movementI of said 4controller ,toA the resulting movement of said surfaces :fin `said -o'ne and said other senses, and altitude responsive means for operating at least one of said ratio adjusting References Cited in the le of this patent UNITED STATES PATENTS Baker Feb. 2, 1915 Mignet June 1, 1937 V311 N68 zza-2;--- 11.11116 25, 1940 Henke Jan. 4, 1944 Vint Nov. 30, 1948 Billington Sept. 12, V1950 Morris Oct. 30, 1951 Feeney et a1 Nov. 24, 1953 McKellar June 8, 1954 Amster et al. July 5, 1955 

